Human RF Exposure Mitigation in Downlink of mmW Cellular Systems
While cellular communications operating at higher frequencies (i.e., above 6 GHz) have been attracting significant research interest, their potentially harmful impacts on human health are not studied as significantly. Few existing studies discussing the human health impacts above 6 GHz paid attention to uplink only, due to close contact of a transmitter to a human body. This paper claims the necessity of thorough investigation in downlink on human exposure to electromagnetic fields (EMFs). Our simulation results suggest the downlink of a Fifth Generation Cellular Mobile Communications (5G) system can generate significantly higher power density (PD) and specific absorption rate (SAR) than the previous generations of wireless systems. Our study also highlights the significance of considering SAR as a metric in evaluation of the EMF exposure at high frequencies. Moreover, this paper proposes a downlink protocol that guarantees the EMF exposure level under a threshold while keeping the data rate above the 5G requirements.